序列化List<LinkedListNode<string>>
是有点的一个奇怪的事情要做 - 通常一个只想序列化底层链表。也许你试图序列化一个表,该表给出了与底层列表不同的顺序?
如果是这样的话,它可能会出现,人们可以使用序列化与PreserveReferencesHandling.All
联合ReferenceLoopHandling.Serialize
节点列表,但是这个失败,因为Json.NET的一些限制:
因此,您需要为您的节点列表中custom JsonConverter
:
public class LinkedListNodeListConverter<T> : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return typeof(List<LinkedListNode<T>>).IsAssignableFrom(objectType);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null)
return null;
var list = (existingValue as IList<LinkedListNode<T>> ?? (IList<LinkedListNode<T>>)serializer.ContractResolver.ResolveContract(objectType).DefaultCreator());
var table = serializer.Deserialize<LinkedListNodeOrderTable<T>>(reader);
foreach (var node in table.ToNodeList())
list.Add(node);
return list;
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var list = (IList<LinkedListNode<T>>)value;
var table = LinkedListNodeOrderTable<T>.FromList(list);
serializer.Serialize(writer, table);
}
}
class LinkedListNodeOrderTable<T>
{
public static LinkedListNodeOrderTable<T> FromList(IList<LinkedListNode<T>> nodeList)
{
if (nodeList == null)
return null;
try
{
var list = nodeList.Where(n => n != null).Select(n => n.List).Distinct().SingleOrDefault();
var table = new LinkedListNodeOrderTable<T>(list);
var dictionary = list == null ? null : list.EnumerateNodes().Select((n, i) => new KeyValuePair<LinkedListNode<T>, int>(n, i)).ToDictionary(p => p.Key, p => p.Value);
table.Indices = nodeList.Select(n => (n == null ? -1 : dictionary[n])).ToList();
return table;
}
catch (Exception ex)
{
throw new JsonSerializationException(string.Format("Failed to construct LinkedListNodeOrderTable<{0}>", typeof(T)), ex);
}
}
public LinkedListNodeOrderTable(LinkedList<T> List)
{
this.List = List;
}
public LinkedList<T> List { get; set; }
public List<int> Indices { get; set; }
public IEnumerable<LinkedListNode<T>> ToNodeList()
{
if (Indices == null || Indices.Count < 1)
return Enumerable.Empty<LinkedListNode<T>>();
var array = List == null ? null : List.EnumerateNodes().ToArray();
return Indices.Select(i => (i == -1 ? null : array[i]));
}
}
public static class LinkedListExtensions
{
public static IEnumerable<LinkedListNode<T>> EnumerateNodes<T>(this LinkedList<T> list)
{
if (list == null)
yield break;
for (var node = list.First; node != null; node = node.Next)
yield return node;
}
}
,并使用以下设置:
var settings = new JsonSerializerSettings
{
Converters = { new LinkedListNodeListConverter<string>() },
};
string json = JsonConvert.SerializeObject(lst, Formatting.Indented, settings);
产生的JSON的样子:
{
"List": [
"Kuku",
"Riku",
"Ok"
],
"Indices": [
0,
1,
2
]
}
请注意,转换器假定列表中的所有节点都是相同底层LinkedList<T>
的成员。如果不会抛出异常。
样品fiddle。
来源
2017-04-09 21:24:33
dbc
你究竟想在这里完成什么? –